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Abstract:

A method for producing a fire resistant thread comprising the steps of:
unwinding a first yarn being a fire resistant polymer from a first spool
onto a first pirn; unwinding a second yarn being a synthetic and/or
natural yarn from a second spool onto a second pirn; unwinding a third
yarn being a synthetic and/or natural yarn from a third spool onto a
third pirn; unwinding the first yarn, the second yarn and the third yarn
from the first pirn, the second pirn and the third pirn; twisting the
first yarn, the second yarn and the third yarn each in a first direction;
twisting the first yarn, the second yarn and the third yarn together in a
second direction to form a three-ply thread; coating the three-ply thread
with a bonding agent in order to form the fire resistant thread; and
collecting the fire resistant thread.

Claims:

1. A method for producing a fire resistant thread comprising the steps
of: unwinding a first yarn being a fire resistant polymer from a first
spool onto a first pirn; unwinding a second yarn being a synthetic and/or
natural yarn from a second spool onto a second pirn; unwinding a third
yarn being a synthetic and/or natural yarn from a third spool onto a
third pirn; unwinding said first yarn, said second yarn and said third
yarn from said first pirn, said second pirn and said third pirn; twisting
said first yarn, said second yarn and said third yarn each in a first
direction; twisting said first yarn, said second yarn and said third yarn
together in a second direction to form a three-ply thread; coating said
three-ply thread with a bonding agent in order to form said fire
resistant thread; and collecting said fire resistant thread.

2. The method for producing a fire resistant thread of claim 1 wherein
said fire resistant polymer being selected from the group comprising: an
aramid, a polyester polyarylate, PBO, melamine formaldehyde, or
combinations thereof.

3. The method for producing a fire resistant thread of claim 1 wherein
said second and third yarns being selected from the group comprising:
cotton, linen, polyamides, polyolefins, polyesters, acrylics,
cellulosics, or combinations thereof.

4. The method for producing a fire resistant thread of claim 1 wherein
said first, second and third yarns being continuous multifilament yarns.

5. The method for producing a fire resistant thread of claim 1 wherein
said fire resistant thread being dyeable.

6. The method for producing a fire resistant thread of claim 1 wherein
said first, second, and third yarns each having a denier in the range of
50 to 450 and having a filament count in the range of 30 to 75; said
first yarn, said second yarn and said third yarn each having a twist in a
first direction being an "S" direction in the range of 8.0 to 12.0 turns
per inch; said first yarn, said second yarn and said third yarn being
combined together with a twist in a second direction being a "Z"
direction in the range of 4.0 to 8.0 turns per inch to form said
three-ply thread.

7. The method for producing a fire resistant thread of claim 6 wherein
said first, second, and third yarns each having a denier in the range of
125 to 250 and having a filament count in the range of 40 to 65; said
first yarn, said second yarn and said third yarn each having a twist in a
first direction being an "S" direction in the range of 9.0 to 10.5 turns
per inch; said first yarn, said second yarn and said third yarn being
combined together with a twist in a second direction being a "Z"
direction in the range of 4.5 to 7.0 turns per inch to form said
three-ply thread.

8. The method for producing a fire resistant thread of claim 7 wherein
said first yarn being an aramid continuous multifilament yarn with a
denier of 200 and a filament count of 40; and said second and third yarns
each being a nylon continuous multifilament yarn with a denier of 200 and
a filament count of 40; said first yarn, said second yarn and said third
yarn each having a twist in a first direction being an "S" direction of
9.2 turns per inch; said first yarn, said second yarn and said third yarn
being combined together with a twist in a second direction being a "Z"
direction of 5.0 turns per inch to form said three-ply thread.

9. A method for producing a fire resistant thread comprising the steps
of: unwinding a first yarn being a fire resistant polymer from a first
spool; winding said first yarn onto a first pirn; unwinding a second yarn
being a synthetic and/or natural yarn from a second spool; winding said
second yarn onto a second pirn; unwinding a third yarn being a synthetic
and/or natural yarn from a third spool; winding said third yarn onto a
third pirn; unwinding said first yarn, said second yarn, and said third
yarn from said first pirn, said second pirn and said third pirn;
tensioning and then twisting said first yarn, said second yarn and said
third yarn each in a first direction; tensioning and then twisting said
first yarn, said second yarn and said third yarn together in a second
direction to form a three-ply thread; coating said three-ply thread with
a bonding agent in order to form said fire resistant thread; and
collecting said fire resistant thread.

10. The method for producing a fire resistant thread of claim 9 wherein
said first yarn being wound onto said first pirn in a cocoon shape; said
second yarn being wound onto said second pirn in a cocoon shape; and said
third yarn being wound onto said third pirn in a cocoon shape.

11. The method for producing a fire resistant thread of claim 9 wherein
said fire resistant polymer being selected from the group comprising: an
aramid, a polyester polyarylate, PBO, melamine formaldehyde, or
combinations thereof.

12. The method for producing a fire resistant thread of claim 9 wherein
said second yarn and said third yarn being selected from the group
comprising: cotton, linen, polyamides, polyolefins, polyesters, acrylics,
cellulosics, or combinations thereof.

13. The method for producing a fire resistant thread of claim 9 wherein
said first, second and third yarns being continuous multifilament yarns.

14. The method for producing a fire resistant thread of claim 9 wherein
said fire resistant thread being dyeable.

15. The method for producing a fire resistant thread of claim 9 wherein
said first and second yarns each having a denier in the range of 50 to
450 and having a filament count in the range of 30 to 75; said first
yarn, said second yarn and said third yarn each being tensioned to
prevent any loops or breaks in the yarn and having a twist in a first
direction being an "S" direction in the range of 8.0 to 12.0 turns per
inch; and said first yarn, said second yarn and said third yarn being
tensioned together to prevent any loops or breaks in the yarns and then
combined together with a twist in a second direction being a "Z"
direction in the range of 4.0 to 8.0 turns per inch to form said
three-ply thread.

16. The method for producing a fire resistant thread of claim 15 wherein
said first, second, and third yarns each having a denier in the range of
125 to 250 and having a filament count in the range of 40 to 65; said
first yarn, said second yarn and said third yarn each being tensioned to
prevent any loops or breaks in the yarns and having a twist in a first
direction being an "S" direction in the range of 9.0 to 10.5 turns per
inch; and said first yarn, said second yarn and said third yarn being
tensioned together to prevent any loops or breaks in the yarns and then
combined together with a twist in a second direction being a "Z"
direction in the range of 4.5 to 7.0 turns per inch to form said
three-ply thread.

17. The method for producing a fire resistant thread of claim 16 wherein
said first yarn being an aramid continuous multifilament yarn with a
denier of 200 and a filament count of 40; said second and third yarns
each being a nylon continuous multifilament yarn with a denier of 200 and
a filament count of 40; said first yarn, said second yarn and said third
yarn each being tensioned to prevent any loops or breaks in the yarns and
having a twist in a first direction being an "S" direction of 9.2 turns
per inch; and said first yarn, said second yarn and said third yarn being
tensioned together to prevent any loops or breaks in the yarns and then
combined together with a twist in a second direction being a "Z"
direction of 5.0 turns per inch to form said three-ply thread.

18. The method for producing a fire resistant thread of claim 9 wherein
said first yarn being an aramid continuous multifilament yarn; and said
second yarn and said third yarn each being a nylon continuous
multifilament yarn.

19. The method for producing a fire resistant thread of claim 9 wherein
said coating step being comprised of the following steps: running said
three-ply thread from a supply creel; passing said three-ply thread
through a first set of stretch rollers; passing said three-ply thread
through a dipping tank which contains a bonding agent; passing said
three-ply thread through a squeegee roller to remove excess bonding
agent; passing said three-ply thread through a first oven to dry said
three-ply thread; passing said three-ply thread through a second oven to
dry said three-ply thread; passing said three-ply thread through a third
oven to dry said three-ply thread; passing said three-ply thread through
a second set of stretch rollers; applying a lubricant to said three-ply
thread resulting in said fire resistant thread; and collecting said fire
resistant thread on a spool.

20. The method for producing a fire resistant thread of claim 19 wherein
said first oven having a temperature in the range of 132.degree. C. to
143.degree. C.; said second oven having a temperature in the range of
143.degree. C. to 154.degree. C.; and said third oven having a
temperature in the range of 154.degree. C. to 166.degree. C.

Description:

FIELD OF THE INVENTION

[0001] The present invention relates to a process for producing a fire
resistant thread.

BACKGROUND OF THE INVENTION

[0002] It has long been a problem in the textile industry to create an
inexpensive, sewable fire resistant thread. The sewing thread should
allow easy movement when tension is applied and ease in needle threading;
should resist friction during sewing; should have sufficient elasticity
to avoid the breaking of stitches; and should have sufficient strength to
hold seams during laundering or dry cleaning and in use. Threads for
special uses may require appropriate treatment. Garments made of
fire-resistant fabrics, for example, may be sewn with thread that has
also been made fire-resistant.

[0003] Such a thread would have a variety of uses including, but not
limited to: sewing mattress parts together, sewing fire fighting gear and
clothing together, and sewing upholstery together. Additional uses for
such a sewable thread include, but are not limited to, seat belts, air
bags, cargo nets, cargo straps, and carpeting. A sewable fire resistant
thread must meet the federal requirements of 16 CFR 1632 and Cal 129 in
order to be used to sew the various components of a mattress together.

[0004] A variety of methods and steps have been used in order to fabricate
a fire resistant thread. The various factors which must be taken into
account when developing a thread are numerous. There are a wide variety
of both synthetic and natural yarns to choose from. Among the yarns,
there are a wide range of thicknesses and finishes to choose from. One
must then determine the proper and optimum number of yarns to combine in
order to form a thread as well as determining the proper and optimum
number of twists and the direction of those twists required to obtain a
thread having the physical and functional characteristics both required
and desired.

[0005] Hence, there exists an unsatisfied need for a method of making a
fire resistant thread.

SUMMARY OF THE INVENTION

[0006] A method for producing a fire resistant thread comprising the steps
of: unwinding a first yarn being a fire resistant polymer from a first
spool onto a first pirn; unwinding a second yarn being a synthetic and/or
natural yarn from a second spool onto a second pirn; unwinding a third
yarn being a synthetic and/or natural yarn from a third spool onto a
third pirn; unwinding the first yarn, the second yarn and the third yarn
from the first pirn, the second pirn and the third pirn; twisting the
first yarn, the second yarn and the third yarn each in a first direction;
twisting the first yarn, the second yarn and the third yarn together in a
second direction to form a three-ply thread; coating the three-ply thread
with a bonding agent in order to form the fire resistant thread; and
collecting the fire resistant thread.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For the purpose of illustrating the invention, there is shown in
the figures a form that is presently preferred; it being understood,
however, that this invention is not limited to the precise arrangements
and instrumentalities shown.

[0008]FIG. 1 illustrates an embodiment of a method for producing a fire
resistant thread.

[0010]FIG. 3 illustrates an embodiment of a method for producing a fire
resistant thread.

DETAILED DESCRIPTION OF THE INVENTION

[0011] Referring to the drawings, wherein like numerals indicate like
elements, there is shown in FIG. 1 an embodiment of a method for
producing a fire resistant thread 10. In this embodiment, the present
invention may be summarized in five major steps: The first step includes
pirn winding 1 which involves the unwinding of each yarn 20 from a spool
followed by winding each yarn 20 on a pirn. The second step includes a
first twisting process 2 during which each yarn 20 is tensioned and then
given a twist in a first direction. The third step includes a second
twisting process 3 during which each of the yarns are combined together,
the yarns are tensioned and then given a twist in a second direction. The
forth step includes a coating process 4 during which the combined yarns
are coated with a bonding agent resulting in a fire resistant thread 10.
The fifth step includes a spooling process 5 during which the fire
resistant thread 10 is collected and spooled. In one embodiment of the
present invention, the five steps described above may be accomplished on
five separate machines. In another embodiment of the present invention,
the five steps described above may be accomplished on one or more
machines.

[0012] Pirn winding 1, as used herein, is the process of taking a larger
supply package of raw material and making it into smaller packages that
will run approximately the same duration. In one embodiment of the
present invention, the pirn is run with a bi-conical taper with a sharper
edge (shoulder). In another embodiment of the present invention, the
taper on the pirn is a cocoon shape with a more dull edge (shoulder). In
another embodiment of the present invention, the smoother shoulder, the
normally coarse para-aramid fiber would make a more evenly distributed
delivery to the first twisting process and allow for the yarn to run
completely without breaking or tangling. In one embodiment of the present
invention, the pirn winding may take place using a machine made by LEMA
LEZZENI (Cossato, Italy) such as machine type CLV/C 200 or a similar
machine.

[0013] First twist process 2 twists the input (pirns) yarns in a first
direction with a certain amount of turns per inch (t.p.i.) and winds them
in a parallel manner preparing these yarns for the second twist process
3. In the first twist process 2, each yarn 20 may have its own individual
tension setting. That is to say that a first yarn 22 is tensioned at one
setting, a second yarn, 24 is tensioned at the same or a different
setting, and a third yarn, 26 is tensioned at the same or a different
setting as the first yarn 22 and/or the second yarn 24. In one embodiment
of the present invention, the first twist process may take place using a
machine made by Thema Systems S.r.l. (Moglia, Italy), such as the DT/140
N Spindle or a similar machine. In one embodiment of the present
invention the amount of tension on the thread is adjusted as is the
percentage of difference between the drive spindles and the overfeed
roll. This adjustment allows for the processing of a high tenacity, low
elongation fiber (e.g. a fire resistant polymer) and a mid tenacity, high
elongation fiber (e.g. a synthetic or natural fiber) to be run together
without bunching or knotting. This adjustment prevents the creation of
loops in the yarns which would make it unlikely that the fire resistant
thread would function as a sewing thread without binding up or breaking
in the needle.

[0014] Second twist process 3 twists the yarns in a second direction (the
opposite direction of the first direction) with a certain amount of turns
per inch (t.p.i.) to create a smooth, even multiple-ply thread. In one
embodiment of the present invention, much like the first twist process 2,
the amount of tension is maintained in a consistent manner allowing for
the full length run of the yarn. Knots or uneven wind at this point would
prohibit the even application of the coating and make proper stitch
formation impossible. In one embodiment of the present invention, the
second twist process 3 may take place using a machine made by Thema
Systems S.r.l. (Moglia, Italy), such as the R 325N DT/100 CE or a similar
machine.

[0015] The coating process 4 coats the combined yarns with a bonding agent
resulting in a fire resistant thread 10. Looking to FIG. 3, in one
embodiment of the present invention, the coating process 4 is
accomplished by running the thread from a supply creel 200, through a
first set of stretch rollers 210, a dipping tank 220, a squeegee 230, a
first oven 240, a second oven 250, a third oven 260, a second set of
stretch rollers 270, over a lick roll lubrication applicator 280 and on
to a final spool 290. In one embodiment of the present invention the
coating process 4 is accomplished on an M&P coating range. In another
embodiment the coating process 4 is modified to allow for the even
stretching of the fire resistant thread 10 without any damage to the
individual fibers. At the same time the process preserves the smoothness
required to make the fire resistant thread sewable. Without these
tensioning adjustments to the coating range, knots would result that
would make the fire resistant thread unusable in any needle application.
In one embodiment of the present invention the coating process may be
carried out on a TAF 52 Bonding machine manufactured by MP s.r.l.
(Urgnano, Italy) or a similar machine.

[0016] The spooling process 5 is the fifth step during which the fire
resistant thread 10 is collected and spooled. Spooling is the act of
placing the fire resistant thread 10 on a serving package designated by
the customer. In one embodiment of the present invention, a final level
of lubrication is applied to the fire resistant thread for optimum
performance. In another embodiment of the present invention the coating
process may be carried out on a spooling machine manufactured by
Texilmesa s.r.l. (Lecco, Italy) or a similar machine.

[0017] Referring again to the drawings, wherein like numerals indicate
like elements, there is shown in FIG. 2 an embodiment of a fire resistant
thread 10. The present invention provides a fire resistant thread. The
fire resistant thread may be comprised of three or more yarns 20 which
may be referred to as a first yarn 22, a second yarn 24 and a third yarn
26. In one embodiment, the first yarn 22 is a filament yarn comprised of
a fire resistant polymer. The second yarn 24 and the third yarn 26 are
each comprised of a synthetic and/or natural yarn. The first yarn 22, the
second yarn 24 and the third yarn 26 individually have a first twist in
the same direction. The first 22, second 24 and third yarns 26 are then
combined using a second twist which is in the opposite direction of the
first twist resulting in a 3-ply thread 50. In one embodiment, the fire
resistant thread is a sewing thread. Sewing thread, as used herein,
refers to a thread which may be used to sew two or more fabrics together.

[0018] The present invention discloses a method for producing a fire
resistant thread 10 comprising the steps of: unwinding a first yarn 22
being a fire resistant polymer from a first spool 100 onto a first pirn
105; unwinding a second yarn 24 being a synthetic and/or natural yarn
from a second spool 110 onto a second pirn 115; unwinding a third yarn 26
being a synthetic and/or natural yarn from a third spool 120 onto a third
pirn 125; unwinding the first yarn 22, the second yarn 24 and the third
yarn 26 from the first pirn 105, the second pirn 115 and the third pirn
125; twisting the first yarn 22, the second yarn 24 and the third yarn 26
each in a first direction; twisting the first yarn 22, the second yarn 24
and the third yarn 26 together in a second direction to form a three-ply
thread 50; coating the three-ply thread with a bonding agent in order to
form the fire resistant thread; and collecting the fire resistant thread.

[0019] Unwinding, as used herein, refers to the process of removing a yarn
or thread from a spool or pirn, preferably without breaking or damaging
the yarn or thread.

[0020] Yarn 20, as used herein, refers to a strand comprised of fibers,
filaments 30, or combinations thereof, natural or synthetic, suitable for
use in sewing threads. In one embodiment, the yarn may be comprised of a
number of fibers twisted together. In another embodiment, the yarn 20 may
be comprised of a number of filaments 30 grouped together but not
twisted. In yet another embodiment, the yarn 20 may be comprised of a
number of filaments 30 twisted together. In still another embodiment, the
yarn 20 may be comprised of a single filament 30, called a monofilament,
either with or without twist. In still another embodiment, the yarn 20
may be comprised of a combination of natural and synthetic fibers. In
still another embodiment, the yarn may be comprised of a combination of
natural and synthetic filaments.

[0021] Fiber, as used herein, refers to units of matter having length at
least 100 times their diameter or width. Typically textile fibers are
units that can be spun into a yarn by various methods including twisting.
Fibers suitable for textile use possess adequate length, fineness,
strength, and flexibility for yarn formation and for withstanding the
intended use of the completed yarn. Other properties affecting fiber
performance include, but are not limited to, elasticity, durability,
uniformity, luster, crimp (waviness), moisture absorption, reaction to
heat and sunlight, reaction to the various chemicals applied during
processing and in the dry cleaning or laundering of the completed fabric,
and resistance to insects and microorganisms. The wide variation of such
properties among textile fibers determines their suitability for various
uses. In one embodiment, fiber may refer to staple. In another
embodiment, fiber may refer to continuous filament and/or tow.

[0022] Filament 30, as used herein, refers to a fiber of an indefinite or
extreme length such as found naturally in silk. Synthetic strands are
extruded into filaments that are converted into filament yarn, staple, or
tow.

[0023] Yarns may be categorized into different types which include single,
ply, or cord. Single, or one-ply, yarns may refer to single strands
composed of fibers and or filaments held together by at least a small
amount of twist. In one embodiment of the present invention, the first,
second, third, or additional yarns may be filaments grouped together
either with or without twist. In yet another embodiment, the first,
second, third, or additional yarns may be synthetic filaments extruded in
sufficient thickness for use alone as yarn (monofilaments). In yet
another embodiment, the first, second, third, or additional yarns may be
continuous multifilament yarns. Single yarns of the spun type, composed
of many short fibers, may be held together with a twist in either S-twist
40 or Z-twist direction 35.

[0024] Ply, plied, or folded, yarns may be composed of two or more single
yarns twisted together. In one embodiment, the fire resistant thread may
be a three-ply thread 50 may be comprised of three single yarns. In yet
another embodiment, the first, second, third or additional yarns are each
twisted in one direction (e.g., the "S" direction 40) and are then
combined and twisted in the opposite direction (e.g., the "Z" direction
35) to make a ply thread. In one embodiment, the fire resistant thread 10
may be comprised of single yarns 20 twisted in the "S" direction" 40
which are then combined and twisted in the "Z" direction 35. In another
embodiment, the fire resistant thread 10 may be comprised of single yarns
20 twisted in the "Z" direction" 35 which are then combined and twisted
in the "S" direction 40.

[0025] Cord yarns may be produced by twisting ply yarns together, with the
final twist usually applied in the opposite direction of the ply twist.
In one embodiment, a fire resistant thread may be a cord yarn having an
SZS form, with S-twisted singles made into Z-twisted plies that are then
combined with an S-twist. In another embodiment, a fire resistant thread
may be a cord yarn having a ZSZ form. In yet another embodiment, a fire
resistant thread may be a cord yarn having an SSZ or a ZZS pattern.

[0026] First yarn 22, as used herein, refers to a yarn, as described
above, which is a filament yarn. Filament yarn, as used herein, refers to
a yarn composed of one or more continuous filaments assembled with or
without a twist. In one embodiment of the present invention, the first
yarn 22 may be comprised of filaments 30 having a first twist in either
the "S" 40 or "Z" 60 direction, made of a fire resistant polymer. In
another embodiment, the first yarn 22 may be comprised of fibers having a
first twist in either the "S" 40 or "Z" 60 direction, made of a fire
resistant polymer. In still another embodiment, the first yarn 22 may be
a monofilament yarn. In still another embodiment, the first yarn 22 may
be a continuous multifilament yarn.

[0027] Fire resistant polymer, as used herein, refers to a polymer that
does not burn at all, burns slowly, or is self-extinguishing after
removal of an external source of ignition. A yarn 20 may be fire
resistant because of the innate properties of the fiber/filament, the
twist level of the yarn, the presence of flame retardants, or a
combination thereof. In one embodiment of the present invention, the
first yarn 22 may be comprised of filaments 30 made of a fire resistant
polymer including, but not limited to, an aramid, a polyester
polyarylate, a PBO, a melamine formaldehyde, or combinations thereof. In
another embodiment of the present invention, the first yarn 22 may be
comprised of fibers made of a fire resistant polymer including, but not
limited to, an aramid, a polyester polyarylate, a PBO, a melamine
formaldehyde, or combinations thereof. In still another embodiment, the
first yarn 22 may be an aramid yarn. In still another embodiment, the
first yarn 22 may be an aramid (e.g., Kevlar made by DuPont Corp. of
Wilmington, Del., USA) continuous multifilament yarn.

[0028] Spool, as used herein, refers to a device used to provide either
temporary or permanent storage for a yarn 20. First spool 100, as used
herein, refers to a spool used to provide either temporary or permanent
storage for a first yarn 22. Second spool 110, as used herein, refers to
a spool used to provide either temporary or permanent storage for a
second yarn 24. Third spool 120, as used herein, refers to a spool used
to provide either temporary or permanent storage for a third yarn 26.

[0029] Pirn, as used herein, refers to a device used to provide either
temporary or permanent storage for a yarn 20. First pirn 105, as used
herein, refers to a pirn used to provide either temporary or permanent
storage for a first yarn 22. Second pirn 115, as used herein, refers to a
pirn used to provide either temporary or permanent storage for a second
yarn 24. Third pirn 125, as used herein, refers to a pirn used to provide
either temporary or permanent storage for a third yarn 26. In one
embodiment of the present invention, a yarn 20 is unwound from a spool
and then wound onto a pirn in order to ensure snag-free delivery of the
yarn. In another embodiment of the present invention, a yarn is wound
onto a pirn into a cocoon shape (FIG. 3) in order to ensure snag-free
delivery of the yarn.

[0030] Second yarn 24, as used herein, refers to a yarn, as described
above, that is either a synthetic yarn, a natural yarn or a combination
thereof. In one embodiment of the present invention, the second yarn 24
may be comprised of filaments 30 having a first twist in either the "S"
40 or "Z" 35 direction. In another embodiment, the second yarn 24 may be
comprised of fibers having a first twist in either the "S" 40 or "Z" 35
direction. The second yarn 24 may be comprised of materials including,
but not limited to, cotton, linen, alpaca, angora, mohair, llama,
cashmere, silk, camel, yak, possum, qiviut, cat, dog, wolf, rabbit,
buffalo hair, polyamides, polyolefins, polyesters, acrylics, cellulosics,
or combinations thereof. In one embodiment of the present invention, the
second yarn 24 may be a continuous multifilament yarn. In another
embodiment, the second yarn 24 may be a nylon continuous multifilament
yarn.

[0031] Synthetic yarn, as used herein, refers to a yarn comprised of
synthetic fibers and/or filaments obtained from man-made sources.
Synthetic fibers/filaments, as used herein, refers to fibers/filaments
made of polymers that do not occur naturally but instead are produced
from by-products of petroleum or natural gas. Synthetic fibers/filaments
may be produced from fiber-forming substances including, but not limited
to, (1) polymers synthesized from chemical compounds; (2) modified or
transformed natural polymers; and (3). Synthetic fibers/filaments
include, but are not limited to, polyamides, polyolefins, polyesters,
acrylics, cellulosics, acetates, rayons, fiberglass, or combinations
thereof.

[0032] Natural yarn, as used herein, refers to a yarn comprised of natural
fibers and/or filaments obtained from non-man made sources. Natural
fibers, as used herein, refer to any hair-like raw material directly
obtainable from an animal, vegetable or mineral source which may be spun
into a yarn. The only filament that is produced in nature is silk. Most
textile fibers are slender, flexible, and relatively strong. They are
elastic in that they stretch when put under tension and then partially or
completely return to their original length when the tension is removed.
Natural fibers include, but are not limited to, cotton, linen, alpaca,
angora, mohair, llama, cashmere, camel, yak, possum, qiviut, cat, dog,
wolf, rabbit, buffalo hair, or asbestos. Natural filaments include silk.

[0033] Third yarn 26, as used herein, refers to a yarn 20, as described
above, that is either a synthetic yarn, a natural yarn, or a combination
thereof. In one embodiment of the present invention, the third yarn 26
may be comprised of filaments 30 having a first twist in either the "S"
40 or "Z" 35 direction. In another embodiment, the third yarn 26 may be
comprised of fibers having a first twist in either the "S" 40 or "Z" 35
direction. The third yarn 26 may be comprised of materials including, but
not limited to, cotton, linen, alpaca, angora, mohair, llama, cashmere,
silk, camel, yak, possum, qiviut, cat, dog, wolf, rabbit, buffalo hair,
polyamides, polyolefins, polyesters, acrylics, cellulosics, or
combinations thereof. In one embodiment of the present invention, the
third yarn 26 may be a continuous multifilament yarn. In another
embodiment, the third yarn 26 may be a nylon continuous multifilament
yarn.

[0034] Twist, as used herein, refers to the spiral arrangement of the
filament(s) and/or fibers around the axis of the yarn. Twist may be
produced by revolving one of a filament/fiber strand while the other end
is held stationary. The twist binds the filaments/fibers together and
enhances the strength of the yarn. The direction of the twist is
described as S-twist 40 and Z-twist 35. A yarn has S-twist 40 if, when
held in a vertical position, the spirals conform to the direction of
slope of the central portion of the letter "S". A yarn has Z-twist 35 if,
when held in a vertical position, the direction of spirals conforms to
the slope of the central portion of the letter "Z." In one embodiment,
the twist may refer to a first twist which may be in either the "S" 40 or
"Z" 35 direction. In another embodiment, the twist may refer to a second
twist which may be a twist in the opposite direction as the first twist.
In still another embodiment, the twist may refer to a third twist which
may be a twist in either the same or the opposite direction as the first
twist.

[0035] In one embodiment of the present invention, the first yarn 22, the
second yarn 24 and the third yarn 26 each have a twist in a first
direction in the range of 8.0 to 12.0 turns per inch. In another
embodiment, the first yarn 22, the second yarn 24 and the third yarn 26
each have a twist in a first direction in the range of 9.0 to 10.5 turns
per inch. In still another embodiment, the first yarn 22, the second yarn
24 and the third yarn 26 each have a twist in a first direction of 9.2
turns per inch.

[0036] In one embodiment, the first yarn 22, the second yarn 24 and the
third yarn 26 are combined together with a twist in a second direction in
the range of 4.0 to 8.0 turns per inch to form a three-ply thread 50. In
another embodiment, the first yarn 22, the second yarn 24 and the third
yarn 26 are combined together with a twist in a second direction in the
range of 4.5 to 7.0 turns per inch to form a three-ply thread. In yet
another embodiment, the first yarn 22, the second yarn 24 and the third
yarn 26 are combined together with a twist in a second direction of 5.0
turns per inch to form a three-ply thread 50.

[0037] Bonding agent, as used herein, refers to a material, such as an
adhesive, used to bond filaments and or fibers to one another. Bonding
agents may include, but are not limited to, polyurethanes, polyethylene
terephthalates, polyacrylics, nylons and other conventional fiber bonding
compositions.

[0038] Multifilament yarn, as used herein, refers to a filament yarn, as
described above, comprised of two or more filaments assembled with or
without a twist. In one embodiment of the present invention, the first
yarn 22, second yarn 24 and third yarn 26 are continuous multifilament
yarns.

[0040] Denier, as used herein, refers to the weight in grams of 9,000
meters of filament or filament yarn. For example, if 9,000 meters of a
yarn weigh 15 grams, it is a 15-denier yarn; if 9,000 meters of a yarn
weigh 100 grams, it is a 100-denier yarn, and much coarser than the
15-denier yarn. Thus a smaller number indicates a finer yarn. In one
embodiment of the present invention, the deniers of the first and second
yarns are roughly equal to one another. In another embodiment, the
deniers of the first, second, and third yarns are roughly equal to one
another. In another embodiment, the denier for the first yarn 22, second
yarn 24 and third yarn 26 is between 50 and 450. In still another
embodiment, the denier for the first yarn 22, second yarn 24 and third
yarn 26 is between 125 and 250. In still another embodiment, the denier
for the first yarn 22, second yarn 24 and third yarn 26 is between 175
and 225. In still another embodiment, the denier for the first yarn 22,
second yarn 24 and third yarn 26 is 80. In still another embodiment, the
denier for the first yarn 22, second yarn 24 and third yarn 26 is 200. In
still another embodiment, the denier for the first yarn 22, second yarn
24 and third yarn 26 is 400.

[0041] Filament count, as used herein, refers to the number of individual
filaments that make up a thread or yarn. In one embodiment of the present
invention, the filament count for the first yarn 22, second yarn 24 and
third yarn 26 is between 30 and 75. In another embodiment, the filament
count for the first yarn 22, second yarn 24 and third yarn 26 is between
40 and 65. In yet another embodiment, the filament count for the first
yarn 22, the second yarn 24 and the third yarn 26 is 40. In still another
embodiment, the filament counts of the second 24 and third yarns 26 are
roughly equal to one another. In still another embodiment, the filament
count of the first yarn 22 is substantially different to the filament
counts of the second 24 and third yarns 26. In still another embodiment,
the filament count of the first yarn 22 is roughly equal to the filament
count of the second 24 and third yarns 26.

[0042] The present invention may be realized in the form of numerous
embodiments. One embodiment of the present invention discloses a method
for producing a fire resistant thread comprising the steps of: unwinding
a first yarn 22 being a fire resistant polymer from a first spool 100;
winding the first yarn 22 onto a first pirn 105; unwinding a second yarn
24 being a synthetic and/or natural yarn from a second spool 110; winding
the second yarn 24 onto a second pirn 115; unwinding a third yarn 26
being a synthetic and/or natural yarn from a third spool 120; winding the
third yarn 26 onto a third pirn 125; unwinding the first yarn 22, the
second yarn 24, and the third yarn 26 from the first pirn 105, the second
pirn 115 and the third pirn 125; tensioning and then twisting the first
yarn 22, the second yarn 24 and the third yarn 26 each in a first
direction; tensioning and then twisting the first yarn 22, the second
yarn 24 and the third yarn 26 together in a second direction to form a
three-ply thread 50; coating the three-ply thread 50 with a bonding agent
in order to form the fire resistant thread 10; and collecting the fire
resistant thread 10.

[0043] In one embodiment of the above method (illustrated in FIG. 3), the
first yarn 22 is wound onto the first pirn 105 in a cocoon shape, the
second yarn 24 is wound onto the second pirn 115 in a cocoon shape and
the third yarn 26 is wound onto the third pirn 125 in a cocoon shape. In
another embodiment of the above method, the fire resistant polymer is
selected from the group comprising: an aramid, a polyester polyarylate,
PBO, melamine formaldehyde, or combinations thereof. In still another
embodiment of the above method, the second yarn 24 and the third yarn 26
are selected from the group comprising: cotton, linen, polyamides,
polyolefins, polyesters, acrylics, cellulosics, or combinations thereof.
In yet another embodiment of the above method, the first 22, second 24
and third 26 yarns are continuous multifilament yarns. In still another
embodiment of the above method, the fire resistant thread 10 is dyeable.

[0044] In one embodiment of the above method for producing a fire
resistant thread 10, the first 22 and second 24 yarns each have a denier
in the range of 50 to 450 and have a filament count in the range of 30 to
75; the first yarn 22, the second yarn 24 and the third yarn 26 each are
tensioned to prevent any loops or breaks in the yarn and having a twist
in a first direction being an "S" direction in the range of 8.0 to 12.0
turns per inch; and the first yarn 22, the second yarn 24 and the third
yarn 26 are tensioned together to prevent any loops or breaks in the
yarns and then combined together with a twist in a second direction being
a "Z" direction in the range of 4.0 to 8.0 turns per inch to form the
three-ply thread 50.

[0045] In another embodiment of the above method for producing a fire
resistant thread 10, the first 22, second 24 and third 26 yarns each have
a denier in the range of 125 to 250 and have a filament count in the
range of 40 to 65; the first yarn 22, the second yarn 24 and the third
yarn 26 each are tensioned to prevent any loops or breaks in the yarn and
having a twist in a first direction being an "S" direction in the range
of 9.0 to 10.5 turns per inch; and the first yarn 22, the second yarn 24
and the third yarn 26 are tensioned together to prevent any loops or
breaks in the yarns and then combined together with a twist in a second
direction being a "Z" direction in the range of 4.5 to 7.0 turns per inch
to form the three-ply thread 50.

[0046] In another embodiment of the above method for producing a fire
resistant thread 10, the first yarn 22 is an aramid continuous
multifilament yarn with a denier of 200 and a filament count of 40; the
second 24 and third yarns 26 each being a nylon continuous multifilament
yarn with a denier of 200 and a filament count of 40; the first yarn 22,
the second yarn 24 and the third yarn 26 each are tensioned to prevent
any loops or breaks in the yarns and have a twist in a first direction
being an "S" direction of 9.2 turns per inch; the first yarn 22, the
second yarn 24 and the third yarn 26 are tensioned together at to prevent
any loops or breaks in the yarns and then combined together with a twist
in a second direction being a "Z" direction of 5.0 turns per inch to form
the three-ply thread 50.

[0047] In one embodiment of the above method for producing a fire
resistant thread, the first yarn 22 is an aramid continuous multifilament
yarn and the second yarn 24 and the third yarn 26 each being a nylon
continuous multifilament yarn.

[0048] In one embodiment of the above method for producing a fire
resistant thread 10, the coating step 4 may be comprised of the following
steps: running the three-ply thread 50 from a supply creel 200; passing
the three-ply thread 50 through a first set of stretch rollers 210;
passing the three-ply thread 50 through a dipping tank 220 which contains
a bonding agent; passing the three-ply thread 50 through a squeegee
roller 230 to remove excess bonding agent; passing the three-ply thread
50 through a first oven 240 to dry the three-ply thread; passing the
three-ply thread 50 through a second oven 250 to dry the three-ply
thread; passing the three-ply thread 50 through a third oven 260 to dry
the three-ply thread; passing the three-ply thread 50 through a second
set of stretch rollers 270; applying a lubricant 280 to the three-ply
thread 50 resulting in the fire resistant thread; and collecting the fire
resistant thread 10 on a spool 290. In another embodiment of the above
methods for producing a fire resistant thread 10, the first oven 240 has
a temperature in the range of 132° C. to 143° C., the
second oven 250 has a temperature in the range of 143° C. to
154° C. and the third oven 260 has a temperature in the range of
154° C. to 166° C. In still another embodiment of the above
methods for producing a fire resistant thread 10, the first oven 240 has
a temperature in the range of 135° C. to 140° C., the
second oven 250 has a temperature in the range of 140° C. to
150° C. and the third oven 260 has a temperature in the range of
150° C. to 162° C. In still another embodiment of the above
methods for producing a fire resistant thread 10, the first oven 240 has
a temperature in the range of 138° C. to 142° C., the
second oven 250 has a temperature in the range of 142° C. to
150° C. and the third oven 260 has a temperature in the range of
150° C. to 158° C.

[0049] One embodiment of the present invention discloses a method for
producing a fire resistant thread comprising the steps of: providing a
first yarn 22 being a fire resistant polymer yarn; providing a second
yarn 24 being a synthetic and/or natural yarn; twisting the first yarn 22
and the second yarn 24 each in a first direction; twisting the first yarn
22 and the second yarn 24 together in a second direction to form a
two-ply thread; coating the two-ply thread with a bonding agent in order
to form the fire resistant thread; collecting the fire resistant thread.
In one embodiment of the present invention the fire resistant polymer
yarn is selected from the group comprising: an aramid, a polyester
polyarylate, PBO, melamine formaldehyde, or combinations thereof. In
another embodiment, the second yarn 24 is selected from the group
comprising: cotton, linen, polyamides, polyolefins, polyesters, acrylics,
cellulosics, or combinations thereof. In still another embodiment, the
first 22 and second yarns 24 are continuous multifilament yarns. In yet
another embodiment, the fire resistant thread 10 is dyeable. In still
another embodiment, the first 22 and second yarns 24 each have a denier
in the range of 50 to 450 and have a filament count in the range of 30 to
75. In yet another embodiment, the first yarn 22 is an aramid continuous
multifilament yarn; and the second yarn 24 is a nylon continuous
multifilament yarn.

[0050] In one embodiment of the present invention, the first twist process
may take place using a machine made by Thema Systems S.r.l. (Moglia,
Italy), such as the DT/140 N Spindle or a similar machine. In another
embodiment of the present invention, each yarn may be tensioned using a
ball yarn tensioner, varying the spindle speed (onto which a yarn is
wound), the type of shape the yarn is wound into on a spindle, or a
combination thereof. In another embodiment, the ball yarn tensioner uses
ball bearings to increase or decrease the amount of tension on one or
more yarns. The ball yarn tensioner is used to regulate the yarn reserve
and compensate for variations in tension. The yarn reserve, as used
herein, has the function of keeping the tension of the yarn constant by
absorbing any irregularities during the unwinding. The yarn reserve is
governed by the number and diameter of ball bearings placed within the
ball yarn tensioner. The fewer the number of ball bearings placed within
the ball tensioner, the longer the reserve. The greater the number of
ball bearings placed within the ball tensioner, the shorter the reserve.
In one embodiment, the ball bearings may be the ones supplied by the
machine manufacturer such as Thema Systems S.r.l. (Moglia, Italy), for
the DT/140 N Spindle or the R 325N DT/100 CE. In another embodiment of
the present invention, the ball bearings may be made of any material,
including, but not limited to, an aramid or a polyamide. In another
embodiment, the ball bearings may range in diameter from 2-12 mm. In
another embodiment, the ball bearings may range in diameter from 4-8 mm.
In another embodiment, the ball bearings may be made of an aramid and
have a diameter of 5 mm or 10 mm. In still another embodiment, the ball
bearings may be made of a polyamide and have a diameter of 5 mm or 10 mm.
In another embodiment of the present invention, the number of ball
bearings placed within the ball yarn tensioner is sufficient enough to
prevent loops in a yarn 20 and at the same time insufficient enough to
cause the yarn 20 to break. In one embodiment of the present invention,
the number of ball bearings placed within the ball yarn tensioner is
adjusted to compensate for factors selected from the group comprising:
temperature, humidity, yarn type, yarn speed, or a combination thereof.
In another embodiment, between 2 and 8 ball bearings are used to tension
each yarn during the first twist process 2. In still another embodiment,
between 2 and 8 ball bearings are used to tension the yarns during the
second twist process 3. In another embodiment of the present invention,
the number of ball bearings placed within the ball yarn tensioner is
sufficient enough to prevent loops in the three yarns 22, 24 and 26 and
at the same time insufficient enough to cause the yarns to break during
the second twist process 3. In one embodiment of the present invention,
the number of ball bearings placed within the ball yarn tensioner is
adjusted to compensate for factors selected from the group comprising:
temperature, humidity, yarn type, yarn speed, or a combination thereof
during the second twist process 3.

[0051] In one embodiment of the present invention, the second twist
process 3 requires two separate tension settings: the first tension
setting is on the three yarns as they pass through a ball yarn tensioner
(much like the individual yarns in the first twist process 2 described
above) and the second tension setting is after the second twist process
is completed and the 3-ply yarn is being wound on a pirn or spindle. In
another embodiment, the second tension setting is achieved by adding
weights to a flyer placed on top of the supply yarns. In still another
embodiment, the weight placed on top of the flyer ranges from 20 to 60
grams. In yet another embodiment, the weight placed on top of the flyer
ranges from 20 to 40 grams. In still another embodiment, the weight
placed on top of the flyer is 20 grams. In yet another embodiment, the
weight placed on top of the flyer ranges is 40 grams. In still another
embodiment, the weight placed on top of the flyer is 60 grams.

[0052] In one embodiment of the present invention, the second twist
process 3 may take place using a machine made by Ratti-Thema Systems
S.r.l., such as the R 325N DT/100 CE. In another embodiment, the second
twist process 3 requires two separate tension settings: the first tension
setting is on the three yarns as they pass through a ball yarn tensioner
(much like the individual yarns in the first twist process 2) and the
second tension setting is after the second twist process is completed and
the 3-ply yarn is being wound on a pirn or spindle.

[0053] In one embodiment, the above method may further comprise the steps
of: providing one or more additional yarns selected from the group
comprising: a fire resistant polymer, a synthetic yarn, a natural yarn,
or a combination thereof; twisting the additional yarn or yarns each in a
first direction; twisting the first yarn, the second yarn, and the
additional yarn(s) together in a second direction to form a multiple-ply
thread; coating the multiple-ply thread with a bonding agent in order to
form the fire resistant thread; and collecting the fire resistant thread.